The use of wireless sensor networks has been expanding rapidly in recent years, fueled by the progress of the standardization of communication technologies for wireless sensor networks, such as IEEE802.15.4 and Zigbee. In the past, it was difficult to realize services for wireless sensor nodes that require interoperation with external networks. This was because the realization of such services involves stringent constraints with respect to the resources and communication functions of nodes such as memory size, CPU performance, and communication with sleep function. However, as device implementation technologies and network technologies for wireless sensor nodes see significant advancement, the development of technologies for enabling interoperation between a wireless sensor network and an external network is becoming increasingly active. For example, through efforts like IETF 6 lowpan, the development and standardization of enabling technologies for IPv6 networking functions over the MAC layer protocol of IEEE802.15.4 are being promoted.
These enabling technologies for IPv6 networking functions are disclosed in, for example, Patent Literatures 1 to 3 listed below:    Patent Literature 1: Japanese Patent Laying-Open No. 2005-204016    Patent Literature 2: Japanese Patent Laying-Open No. 2006-148241    Patent Literature 3: Japanese Patent Laying-Open No. 2006-238300
When promoting the realization of large-scale and practical ubiquitous services for homes and businesses, issues that must be addressed are: (i) reduction of administrative load involved in the operation of a wireless sensor network and (ii) enabling of outsourcing of various services. As efforts are made to solve these issues, increased importance would be given to functions to perform runtime configuration on wireless sensor nodes remotely from a service server and those to enable a wireless sensor node and a service server to communicate with each other.
These functions can be realized by incorporating IPv6 into a wireless sensor network, because, an IPv6ed wireless sensor node is able to communicate directly with a remote service server.
However, considering the case that a wireless sensor node can move freely among service domains and change the service server to communicate, it is generally difficult for the node to previously have the addresses or other information of service servers that is necessary to connect to them. In order for the service server to perform runtime configuration on a wireless sensor node, the wireless sensor node is required to perform several processes after completing the connection process to connect to a wireless sensor network at the MAC layer and therebelow. These include the processes of: configuring settings for connection, such as determining an IP address with which to utilize the IPv6 networking functions; acquiring the service server's connection information and connecting to the service server; and acquiring configuration information from the service server and reflecting the acquired configuration information.
These processes, if performed directly by individual wireless sensor nodes separately, will lead to an increase in the number of wireless communications performed by each wireless sensor node and its operation time. Such increase will hinder the efforts being made to reduce power consumption by a wireless sensor node by way of reducing the operation time and the number of wireless communications. It is, therefore, necessary to realize an efficient processing scheme for such processes.
An object of the present invention is to provide an autoconfiguration system for a wireless sensor network and its method and a gateway apparatus for a wireless sensor network, which enable connection between a wireless sensor node and a service server while reducing load on the wireless sensor node.